Dressing device and method for dressing a grinding tool

ABSTRACT

A dressing device for profiling and sharpening a grinding tool includes a rotatable sharpening tool and a rotatable profiling tool axially offset from and settable relative to the rotatable sharpening tool. In one embodiment, the rotatable sharpening tool and the rotatable profiling tool have a common rotational axis, and the tools are settable along the common rotational axis. In another embodiment, a profiling tool axis of rotation is parallel to a sharpening tool axis of rotation. A method for dressing a grinding tool is also disclosed. The method includes profiling and sharpening the grinding tool with a single dressing device having a rotatable profiling tool with a first feed rate and a first advancement rate, and a rotatable sharpening tool with a second feed rate and a second advancement rate. The two feed rates or the two advancement rates are different.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the United States National Phase of PCT Appin. No. PCT/DE2019/101024 filed Nov. 29, 2019, which claims priority to German Application No. DE102018130908.2 filed Dec. 5, 2018, the entire disclosures of which are incorporated by reference herein.

TECHNICAL FIELD

The disclosure relates to a dressing device designed for profiling and sharpening a grinding tool. The disclosure further relates to a method for dressing a grinding tool.

BACKGROUND

A dressing device of the generic type is known from U.S. Pat. No. 4,073,281 A, for example. In a first variant of the known dressing device, a dressing roller and a sharpening roller are attached to a common spindle. In a further variant of the dressing device according to U.S. Pat. No. 4,073,281 A (FIG. 8), the dressing roller and the sharpening roller rotate about mutually parallel axes, both rollers being driven by means of a single belt. In this case, no axial offset is provided between the two rollers. The devices according to U.S. Pat. No. 4,073,281 A are suitable for machining grinding wheels made of cubic boron nitride (CBN).

A further dressing device, which is also provided for machining CBN grinding wheels, is disclosed in U.S. Pat. No. 4,259,940 A. A roller provided for dressing (truing wheel) can hereby rotate with a certain direction of rotation. Furthermore, the device according to U.S. Pat. No. 4,259,940 A comprises a roller for finishing (dressing roll), which rotates in the opposite direction if it is used for processing. The two processing tools, i.e., said roller and said roll, are fastened next to one another on a common work spindle.

SUMMARY

Dressing is understood to mean the combination of profiling and sharpening a grinding tool. Correspondingly, in a basic concept known per se, the dressing device comprises two rotatable tools, namely a profiling tool and a sharpening tool. The tools have axes of rotation that are parallel to one another, which also includes an identity of the axes of rotation. The tools are offset from one another in the axial direction of the axes of rotation. According to the disclosure, the profiling tool can be set relative to the sharpening tool. There may be an adjustability between these tools at least in the common axial direction of the tools.

Depending on the embodiment of the dressing device, the adjustability between the two tools can be used either to dress and sharpen the grinding wheel in succession or to use the profiling tool and the sharpening tool simultaneously—in different surface areas of the grinding tool.

According to one possible embodiment, the two tools, i.e., the profiling tool and the sharpening tool, have a common axis of rotation along which they can be set relative to one another. In this case, a non-rotatable coupling between the two tools can be released or could not be provided from the start. For example, this enables one of the tools to be driven while the other tool is at a standstill.

Independently of the arrangement of the tools with respect to one another, tool drives can be implemented to allow the speed of one tool to be varied in relation to the speed of the other tool. For example, each tool is driven by its own electric motor for this purpose. If the two tools of the dressing device have non-identical axes of rotation that are parallel to one another, then these axes of rotation can be set with respect to one another.

According to a first variant, the axes of rotation of the tools lie in a common plane with the axis of rotation of the grinding tool in each operating state. In this case, both the distance between the axis of rotation of the profiling tool and the axis of rotation of the grinding tool, and the distance between the sharpening tool and the axis of rotation of the grinding tool may be variable.

According to a second variant, the axis of rotation of the profiling tool lies in a first plane with the axis of rotation of the grinding tool, and the axis of rotation of the sharpening tool lies in a second plane with the axis of rotation of the grinding tool. An acute angle is enclosed between the two planes, for example, an angle of less than 45°, in particular an angle of less than 30°. An adjustability between the axes of rotation of the profiling tool and the grinding tool is provided, for example, in that the two axes of rotation of the tools of the dressing device are displaceable within the relevant plane. It is also possible to implement embodiments in which, alternatively or in addition, the two planes are pivotable relative to one another, wherein the axis of rotation of the grinding tool represents the pivot axis.

The sharpening tool of the dressing device has, for example, corundum as a cutting material. The grinding tool to be processed may contain cubic boron nitride in a ceramic bond.

The method according to the disclosure generally includes the processes of profiling and sharpening, both processes being carried out by the dressing device which has the profiling tool and the sharpening tool. The tools are fed and advanced relative to the grinding tool. The feed direction forms a right angle with the advancement direction. At least one of the variables of feed and advancement is set differently in the case of the two tools.

The dressing device may be suitable for machining grinding tools for centerless throughfeed grinding. The combination of profiling and sharpening provides the grinding system with a sharpenable tool at an early stage. Compared to conventional methods, which rely on a longer free grinding of the grinding tool, the dressing device according to the disclosure allows for a drastic shortening or even omission of the free grinding. The resulting process of sharpening by means of the variable sharpening tool integrated into the dressing, used simultaneously with the profiling tool or independently of the profiling tool, mainly removes bond components from the grinding tool. This increases the effective roughness depth of the grinding tool, which allows for a workpiece to be machined with low grinding forces.

BRIEF DESCRIPTION OF THE DRAWINGS

Below, three exemplary embodiments of the disclosure are explained in more detail by means of a drawing. In the figures:

FIG. 1 shows components of a dressing device as well as a grinding tool to be processed in plan view,

FIG. 2 shows the arrangement according to FIG. 1 in a perspective view,

FIGS. 3 and 4 show a second exemplary embodiment of a dressing device in views analogous to FIGS. 1 and 2,

FIGS. 5 and 6 show a third exemplary embodiment of a dressing device in views analogous to FIGS. 1 and 2.

DETAILED DESCRIPTION

Unless otherwise stated, the following explanations relate to all exemplary embodiments. Parts that correspond to each other or have basically the same effect are marked with the same reference symbol in all figures. The same applies to the identification of geometric structures.

In the figures, a grinding tool 3 is shown, which is made of cubic boron nitride (CBN) with a ceramic bond. To dress the grinding tool 3, a dressing device 1 is used, of which only two tools 4, 5 are shown, namely a profiling tool 4 and a sharpening tool 5. The profiling tool 4 is rotatable about an axis of rotation RP; the sharpening tool 5 is rotatable about an axis of rotation RSc. The axis of rotation of the grinding tool 3 is denoted by RA. All axes of rotation RA, RP, RSc are aligned parallel to one another in all exemplary embodiments and in all operating states.

In the exemplary embodiment according to FIGS. 1 and 2, the axes of rotation RP, RSc coincide geometrically. The two tools 4, 5 are moved here independently of one another. Each tool 4, 5 of the dressing device 1 has its own electric drive. The tools 4, 5 are displaceable independently of one another along the common axis of rotation RP, RSc. The distance between the axis of rotation RP, RSc of the tools 4, 5 and the axis of rotation RA of the grinding tool 3 can be set.

In the embodiment according to FIGS. 1 and 2, one of the tools 4, 5 may be used for machining the grinding tool 3, while the other tool 5, 4 remains in a waiting position.

In the exemplary embodiment according to FIGS. 3 and 4, no adjustment of the axial distance is provided between the tools 4, 5 of the dressing device 1. In contrast, the axes of rotation RP, RSc are displacable parallel to one another. In the configuration according to FIGS. 3 and 4, the axes of rotation RP, RSc coincide. Based on this configuration, it is possible to move only one of the two tools 4, 5 onto the grinding tool 3 in the radial direction of the axis of rotation RA. If the relevant tool 4, 5 is then moved in the longitudinal direction of the rotational axes RP, RSc, the other tool 5, 4 also performs this movement in the axial direction, and can remain out of engagement with the grinding tool 3. In a modified execution of the method, it is also possible to use the dressing device 1 according to FIGS. 3 and 4 to bring the tools 4, 5 into engagement with the grinding tool 3 simultaneously, i.e., to profile and sharpen the grinding tool 3 in a single pass by means of the synchronously operated tools 4, 5.

FIGS. 5 and 6 show an exemplary embodiment in which the tools 4, 5 are rotatable about spaced apart axes of rotation RP, RSc and are movable independently of one another along these axes of rotation RP, RSc. Each axis of rotation RP, RSc of the dressing device 1 can be set with respect to the axis of rotation RA of the grinding tool 3.

In the design according to FIGS. 5 and 6, a first plane is defined by the axes of rotation RA, RP. A second plane is defined by the axes of rotation RA, RSc. An acute angle is formed between these planes, which intersect in the axis of rotation RA, which in the exemplary embodiment is less than 30 degrees.

In all designs, the control and synchronization of the tools 4, 5 to be carried out is accomplished via the machine control of the dressing device 1. The sharpening tool 5 contains corundum as a cutting material and can also be used to clean the grinding tool 3.

REFERENCE NUMERALS

1 Dressing device

3 Grinding tool

4 Profiling tool

5 Sharpening tool

RA Axis of rotation of the grinding tool

RP Axis of rotation of the profiling tool

RSc Axis of rotation of the sharpening tool 

1.-10. (canceled)
 11. A dressing device for profiling and sharpening a grinding tool, comprising: a rotatable sharpening tool; and a rotatable profiling tool axially offset from and settable relative to the rotatable sharpening tool.
 12. The dressing device of claim 11, wherein: the rotatable sharpening tool and the rotatable profiling tool have a common rotational axis; and the rotatable profiling tool is settable relative to the rotatable sharpening tool along the common rotational axis.
 13. The dressing device of claim 12, wherein the rotatable sharpening tool is decoupled from the rotatable profiling tool with regards to rotation.
 14. The dressing device of claim 11, wherein: the rotatable sharpening tool comprises a sharpening tool axis of rotation; and the rotatable profiling tool comprises a profiling tool axis of rotation, parallel to the sharpening tool axis of rotation.
 15. The dressing device of claim 14, wherein the sharpening tool axis of rotation and the profiling tool axis of rotation can be set relative to one another.
 16. The dressing device of claim 14, further comprising the grinding tool comprising a grinding tool axis of rotation, wherein the sharpening tool axis of rotation, the profiling tool axis of rotation, and the grinding tool axis of rotation lie on a common plane.
 17. The dressing device of claim 14, further comprising the grinding tool comprising a grinding tool axis of rotation, wherein: the profiling tool axis of rotation lies in a first plane with the grinding tool axis of rotation; the sharpening tool axis of rotation lies in a second plane with the grinding tool axis of rotation; and the first plane and the second plane enclose an acute angle.
 18. The dressing device of claim 11, wherein: the rotatable sharpening tool comprises a cutting material; and the cutting material is conundrum.
 19. A method for dressing a grinding tool, comprising profiling and sharpening the grinding tool with a single dressing device, the single dressing device comprising: a rotatable profiling tool with a first feed rate and a first advancement rate; and a rotatable sharpening tool with a second feed rate and a second advancement rate, wherein: the first feed rate is different than the second feed rate; or the first advancement rate is different than the second advancement rate.
 20. The method of claim 19, wherein the rotatable profiling tool and the rotatable sharpening tool simultaneously machine the grinding tool.
 21. The method of claim 20, wherein the grinding tool is a grinding wheel comprising cubic boron nitride. 